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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

``Preferential{''} ammonium uptake by sugarcane does not increase the N-15 recovery of fertilizer sources

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Boschiero, Beatriz Nastaro [1] ; Mariano, Eduardo [1] ; Ocheuze Trivelin, Paulo Cesar [1]
Total Authors: 3
[1] Univ Sao Paulo, Ctr Nucl Energy Agr, Lab Stable Isotopes, Av Centenario 303, CP 96, BR-13416000 Piracicaba, SP 13416000 - Brazil
Total Affiliations: 1
Document type: Journal article
Source: PLANT AND SOIL; v. 429, n. 1-2, SI, p. 253-269, AUG 2018.
Web of Science Citations: 4

Aims As ammonium (NH4+) has been reported as the ``preferred{''} mineral N source for sugarcane (Saccharum spp.), the predominant supply of NH4+ has been hypothesized as a means of increasing the N-15 recovery and crop yield. We aimed to evaluate the N-15 recovery by sugarcane as affected by N-15-NH4+ and N-15-NO3- addition. Methods Under field conditions, N-15-labeled ammonium nitrate {[}labeling as (NH4NO3)-N-15 (N-15-NH4+) and NH4 (NO3)-N-15 (N-15-NO3-)] and urea were surface-applied at a rate of 100 kg N ha(-1). Under controlled conditions, sugarcane was grown in hydroponic medium (containing unlabeled N) until the maximum N demand period. Subsequently, plants received N-15-NH4+ or N-15-NO3- (as ammonium nitrate). Plants were then sampled at 1, 3, 7, and 15 d after fertilization (DAF) to estimate N-15 recovery. Results Under field conditions, the N-15 recovery for urea was lower than that for ammonium nitrate, partly explained by ammonia volatilization, but there was no difference in N use efficiency between the two fertilizer N sources, as well as between N-15-NH4+ and N-15-NO3- supply. Under controlled conditions, however, N-15-NH4+ resulted in higher N-15 recovery than N-15-NO3- until 7 DAF. Nevertheless, as N-15-NH4+ became depleted in the nutrient solution, N-15-NO3- was taken up more intensely by the crop. At 15 DAF, highest N-15 recovery was detected in the roots and whole plant under N-15-NO3- supply. Conclusions Although uptake of NH4+ is faster than NO3-, the so-called ``preference{''} for NH4+ by the crop did not necessarily translate into higher N-15 recovery. Therefore, we suggest that the term ``preference{''} should be used with caution to avoid misinterpretation. (AU)

FAPESP's process: 13/17278-1 - Nitrogen fertilization of sugarcane ratoon: long-term effects of sources and rates of nitrogen fertilizers
Grantee:Beatriz Nastaro Boschiero
Support type: Scholarships in Brazil - Doctorate